ON THE ACCURACY OF INDEX NUMBERS

Index number accuracy is affected by formula specification and sampling error. The authors argue that an index formula should be "ideal" and "exact" (with reference to the range of economically plausible aggregator functions) to be economically justified. These indices are invariant in the homothetic case, as well as in certain non-homothetic scenarios. Empirically, based on foreign trade data for Egypt from 1885-1961, the set of economically justified indices are virtually identical, supporting the theoretical argument that "instrumental error" or "formula variance" should be a negligible factor contributing to index number error. In a discussion of sampling error, on the other hand, the authors criticize earlier work and propose an upper and lower bound. Using the same data, these limits imply that sampling error may be a serious problem for many indices.     

Inference in Cointegrating Models: UK M1 Revisited

The paper addresses the practical determination of cointegration rank. This is difficult for many reasons: deterministic terms play a crucial role in limiting distributions, and systems may not be formulated to ensure similarity to nuisance parameters; finite-sample critical values may differ from asymptotic equivalents; dummy variables alter critical values, often greatly; multiple cointegration vectors must be identified to allow inference; the data may be I(2) rather than I(1), altering distributions; and conditioning must be done with care. These issues are illustrated by an empirical application of multivariate cointegration analysis to a small model of narrow money, prices, output and interest rates in the UK.     

Power of Tests for Unit Roots in the Presence of a Linear Trend*

Dickey and Fuller [Econometrica (1981) Vol. 49, pp. 1057–1072] suggested unit‐root tests for an autoregressive model with a linear trend conditional on an initial observation. TPower of tests for unit roots in the presence of a linear trendightly different model with a random initial value in which nuisance parameters can easily be eliminated by an invariant reduction of the model. We show that invariance arguments can also be used when comparing power within a conditional model. In the context of the conditional model, the Dickey–Fuller test is shown to be more stringent than a number of unit‐root tests motivated by models with random initial value. The power of the Dickey–Fuller test can be improved by making assumptions to the initial value. The practitioner therefore has to trade‐off robustness and power, as assumptions about initial values are hard to test, but can give more power.     

The role of implied volatility in forecasting future realized volatility and jumps in foreign exchange,stock, and bond markets

We study the forecasting of future realized volatility in the foreign exchange, stock, and bond markets from variables in our information set, including implied volatility backed out from option prices. Realized volatility is separated into its continuous and jump components, and the heterogeneous autoregressive (HAR) model is applied with implied volatility as an additional forecasting variable. A vector HAR (VecHAR) model for the resulting simultaneous system is introduced, controlling for possible endogeneity issues. We find that implied volatility contains incremental information about future volatility in all three markets, relative to past continuous and jump components, and it is an unbiased forecast in the foreign exchange and stock markets. Out-of-sample forecasting experiments confirm that implied volatility is important in forecasting future realized volatility components in all three markets. Perhaps surprisingly, the jump component is, to some extent, predictable, and options appear calibrated to incorporate information about future jumps in all three markets.     

Non-price strategic behavior: the case of bank branches

We perform an empirical study of banks’ branching decisions as a strategic non-price variable in an oligopolistic setting. Using panel data of banks from Norway, we find clear evidence that banks act strategically in their branching decisions, taking into consideration the future response from rival banks. The analysis is applied to a unique data set which covers the entire banking sector during both pre- and post-banking crisis periods, where very different types of conduct are found in each of these periods both for banks and borrowers. Moreover, we find that a bank specific branch-network does not confer externality on other banks. As a result branch network affects only market shares but not market size.     

Forecasting in an Extended Chain‐Ladder‐Type Model

Reserving in general insurance is often done using chain‐ladder‐type methods. We propose a method aimed at situations where there is a sudden change in the economic environment affecting the policies for all accident years in the reserving triangle. It is shown that methods for forecasting nonstationary time series are helpful. We illustrate the method using data published in Barnett and Zehnwirth (2000, pp. 245–321). These data illustrate features we also found in data from the general insurer RSA during the recent credit crunch.     

Environmental Innovations in Small and Medium Sized Enterprises

Supporting and accelerating the adoption and diffusion of environmental innovations amongst small and medium sized enterprises (SMEs) is a major challenge to environmental policy makers. Research suggests that whilst SMEs possess high flexibility, their innovative capacity may be limited to incremental changes within their existing technology system and network. Twenty case studies examining the innovation adoption process in SMEs in four sectors and in five countries within the ENVIS project (commissioned by the EU) revealed great variety in factors driving this process. Findings indicate that this variation can be attributed to the character of the environmental innovation, the specific business opportunity, the regulatory setting and pressure experienced by the sector. Based on these findings an analytical framework is suggested, whereby the environmental innovative capability of SMEs is conceived as the result of an interplay between the competencies, the network relations and the strategic orientation of the company (the 'dynamic triangle'). This indicates that policy to support SME's adoption of environmental innovations has to take an integrated form, i.e. addressing and developing competence, networks and strategic orientation of SMEs simultaneously whilst remaining systemic and context sensitive.